A casita is a detached, freestanding structure — typically a guest house with its own entrance, bedroom, bathroom, and sometimes a kitchen. It operates as an independent living space. A room addition is built onto the existing home, expanding its footprint with new bedrooms, living areas, or primary suites. The estate-scale lots in Southern Highlands and Spanish Trails frequently support either option. Both require Clark County permits and, in most communities, HOA approval. Kingdom & Co. designs and builds both types.